Split-thickness skin grafting is the established medical method to deal with large wounds, but it requires enough healthy donor skin to cover the whole wound – something which is not always available.

There are a large number of tissue-engineered skin substitutes, but they are not currently used in clinical settings.

Associate professor Dr Axel Guenther, who worked with the PhD student Navid Hakimi under the supervision of Dr Marc Jeschke, said the medical requirements were too much for those substitutes however.

“Most current 3D bioprinters are bulky, work at low speeds, are expensive and are incompatible with clinical application,” Dr Guenther said.

The team believe their handheld device can overcome these barriers as it weighs less than a kilogram and requires minimal operator training.

Image:The printer at work on a petri dish, leaving lines of collagen and fibrin

It resembles a white-out tape dispenser, but instead of tape there is a tiny device which forms tissue sheets.

There are vertical stripes of “bio ink” which is composed of protein-based biomaterials. Collagen, the most abundant protein in the dermis, and fibrin, a protein involved in wound healing, run along the inside of each tissue sheet.